
Fistbeard McBeardfist |
Other means of controlling undead creatures, such as Command Undead (spell or feat) or the animator's control over his creations, seem to require speech but be independent of language. It's worth noting that zombies not only know no languages, but are actually incapable of knowing languages. Extending that no-language verbal communication to the Undead Bloodline charmer seems the most reasonable way to rule it.

Claxon |

Yeah, zombies have no int so they do not know and are not capable of understanding language.
However, the magic used to control/animate them somehow gets around this and allows the caster to control them. It's magic.
I'd imagine the only way for it to work is that the bloodline's special powers work the same way.

Claxon |

Eh...it's a weird case and a poorly laid out ability.
Charm person makes people treat you like a close friend.
It doesn't matter how close a friend someone is, the probably wont help you kill their family (unless they already have a grudge against them).
Mindless Undead like zombies, don't have a mind or thoughts. There is nothing to like or dislike. You can't be a friend to them.
These two things are at odds, with no clear way to resolve it.
I would probably have the zombie's "personality" be based on the last commands it was giving with your charm having to deal with that.